And charles



(No Model.) 2 Sheets-Sheet 1.

Gr. W. GOY.

TELEPHONE EXCHANGE.

No. 249,015. Pte-Med Nov. 1,1881.

N. paens, Phuwumngmpher. minimo". n. c.

v 2 Sheets-Sheet 2; G. W. COY.

Patented Nov. 1, 1881.

nq VENTDR -P 1D.. -..P D u TELEPHONE EXGHANGE.

(No Model.)

WIT NESSES:

UNITEE SrarEs PATENT EErcE. l

GEORGE COY, OF MILFORD, CONNECTICUT, ASSIGNOR OF TWO-THIRDS TO JAMES G. SMITH, OF HACKENSACK, NE\V JERSEY, AND CHARLES E. BUELL, OF NEW HAVEN, CONNECTICUT.

TELEPHONE-EXCHANGE.

SPECIFICATION forming part of Letters Patent No. 249,015, dated November 1, 1881.

Application rnea .time 15,1881. (No model.)

To all whom it may concern Be it known that I, GEO. W. COY, a citizen of the United States, and a resident of Milford, in the county of New Haven, State of Connectient, have invented certain new and useful Improvements in Telephone Exchanges, of which the following is a specification.

Myinvention consists in a novel arrangement of lines and of the charging or signaling batro tery located at the central oee, whereby I am enabled to dispense entirely with the use ot' ground connecting-wires for the central-office switch, thus producing an exchange system novel in its Operation and of simple character.

x5 Other advantages attendant upon my system will be made apparent.

In carrying out my invention I chargeV the lines of the system from both poles of the eentral-ofce battery, and I complete the circuit 2o of any given line connected to one pole of the battery through some other line or lines connected to the other pole. In some cases I ground the distant terminals of the various lines. In others I connect the lines in pairs at their distant end by a connecting-wire, so that the various pairs of lines constitute normally complete metallic circuits, each ot' which includes the charging-battery at the central office. The arrangements ot' the apparatus at the subscribersstations may be varied in many ways,

and central-nce connecting-switches ot' variousconstructionsmay beemploycd. Thesubscribers stations may be connected for oral communication bygrounding the telephones at the two stations in communication, or the telcphone may be switched into and out ofthe linecircuit passing through all the stations otl the line upon which it is placed.

Figurelrepresents adiagram ot' a telephone- 40 exchange system embodying my invention, and Fig.2 a diagram ot' another arrangement ot' the details.

In Fig.1 the lines are normally connected in pairs at their remote terminals, the two lines 4 5 in each pair being connected at the central ofce to opposite poles ot the charging-battery M B. In Fig. 2 the remote terminals of the various lines are grounded, while at the cen tral office some are connected to one pole and others to the opposite pole of the charging- 5o battery. Under this arrangement the charging-current upon any line connected, say, to the positive pole of the battery is returned to the battery through any or all of the lines connected to the opposite pole. As in the proper operation of the system two or more lines are always connected to each pole of the battery, the breaking of the circuit of any one of them for the purpose ot' signaling to or from the central office will notalfect the bells upon any other, 6c since the charging-current upon the other line is still free to flow upon the unbroken lines.

Referring to Fig.1 of the drawings, M B represents the charging or signaling battery at the central oice, onepoleot' which is connected 65 to a metallic strip, P, and the other pole to a strip, N. The various lines may be connected with or disconnected from either of these strips at pleasure by means ofthe levers S S2 S3, &c., whose pivots are connected with the various 7o lines 1 2 3, &c., as shown. C C represent linecounecting strips, and 9 the connecting switchlevers, by which any two subscribers may be placed in oral communication in a well-known manner. 7 5

The various lines are indicated by the figures 1 to 6, inclusive, while A and B represent subscribers stations upon the various lines. At the central office each line passes through a bell and visual indicator, B B, a spring-jack, J, 8o by means ot' which telephone apparatus M may be introduced into 4the line in the manner described in reissued Letters Patent oi' the United States granted to me June 14,18S1,No.9,764, and through a cireuitbreaking key, C K, by 85 means of which subscribers may be called 7 from the central oftice. The lines arejoined in pairs at their distant terminals by aconductingwire, line 1 to line 2,1ine 3 to line4, and line 5 to line b'. At the central ofce line lis connected 9o tonegativepoleofthecharging-battery through lever S and strip N, while line 2 is similarly connected to the positive pole by S2 and P. In the same manner line 3 is connected to the positive pole, and line 4 to the negative pole, 95 line 5 to the positive, and line 6 to the negative. Each pair of lines thus constitutes acomplete circuit charged by the main battery M B.

Each subscribers station is equipped with a circuit-breakin g key, K, a call-bell, b, and telephone apparatus m, of any approved construction. As here shown, the bell and the telephone areplaced in loop-circuits,while aswitchlcver, 10, whose pivot is connected to the line upon the side of the station remote from the central office, serves to place the bell into or out of circuit, or to connect the main line to earth, for the purpose of oral communication between the subscribers at any two stations whose switch-levers are similarly placed, and for the further purpose ot' producing a circuit whereby other subscribers upon the same pair of lines may signal to the central ottice without disturbing conversation, in the manner to be presently described.

At the central office the charging-battery is connected to the strips P and N through a pole-changing device of well-known construction. Strips C C, adjoining P and N, are shown as provided with similar devices, and may, if desired, be also connected to a charging-battery to be used for charging other lilies.

The general operation of the system is as follows: Let it be supposed that oral communication is desired between A of line 1 and A of line 4. Signals are given to and from the central office in the ordinary manner by breaking the charged circuits upon which those stations are placed. The telephone at either station is placed in the direct or metallic circuit for oral communication with the central office by turning the switch 10, so as to disconnect the loop containing the bell. For the purpose of oral communication between the two stations the switch 10 at each station is turned to connect the line to earth, while at the central otce Sl and S are disconnected from N and from the negative pole of the battery, and the lines 1 and 4 connected by switches 9 and a line-connecting strip, G. Under these conditions the two subscribers are orally connected through the lines and earth in the manner now in ordinary use. In order that stations A and B of lines 2 and 3 and stations B of line 1 and 4 may be still free to signal the central oftice, either S2 or S3 at the central oftice is turned into connection with strip N. Charged circuits are thus formed from the negative pole ot' the battery (in case S2 be connected with N) through A and B of line 2, B of line 1, and switch 10 of A, line 1, to earth, andfrom thepositive pole ofthe battery throu gh A and B of line. 3,13 of line 4, and to earth through the switch-lever 10 of A, line 4, so that either of the stations may signal to the central oiiice by interruption of the line in the ordinary manner without interrupting the conversation taking place between stations A of lines 1 and 4. Station B, line l, might be similarly connected to A or B of line 4, and vice versa. In this case, however, station A ofthe line upon which station B is connected orally would not be free to signal to the central office.

To prevent interruption to conversation on the part of subscribers placed between the central office and the two in communication, devices substantially like those described in Letters Patent of the United States granted to George W. Coy, March 1, 1881, No. 238,361, may bc employed.

In the case ot' oral communication between a station ot' line 2 and a station of line 4, switches S2 and S* would be disconnected from the batterystrips and the lines connected through a line-strip, C. The switches S and S3 of lines 1 and 3 being normally upon opposite battery-strips, it would not be necessary to disturb them, the charging-circuit for lines 1 and 3 being in this case from negative pole of the battery through N, S', line 1, connecting terminal wire. line 2, and to the switch-lever 10 ot' the station upon that line, whose telephone apparatus is grounded for oral communication, and from positivepole of the battery through line 3, to line 4, and to a switch, 10, of that line which is for the time connected to ground. As will be seen, in neither case is the circuit through the telephone of the subscribersin communication, since theline is grounded in every case at a point beyond the telephone. In a similar manner a station upon line 3 might be connected with a station upon line 6 by disconnecting S3 and S6 from the battery-strips. In this case, also, it would not be necessary to disturb levers S4 and Si in order to make it possible for subscribers upon lines 4 and 5 and upon lines 3 and 6 at a point beyond the stations orally connected to signal to the central station.

Where many lines are employed and many subscribers are simultaneously connected itI will be very seldom necessary to shift the battery switch-levers from one poe to the other, sincein almost every case it will be found that the portion of a grounded metallic circuit not in use is connected to an opposite pole of the battery from that of other grounded circuits. When several grounded circuits are thus simultaneously connected to each pole, abreak of circuit upon one of them will not sound the bell upon others, as will be more readily understood when the similar conditions obtaining with the use ot'norm all ygrounded circuits are described.

In order to allow subscribers upon the same pair of circuits to communicate, itis only nec essary to disconnect their battery switch-levers at the central office and join the lines through a line-strip, C, the levers 10 at the stations being placed in a position between the ground-stud and the stud connected with the loop containing the bell.`

In Fig. 2 the central-ottico apparatus is the same as in Fig. 1. Each line is, however, grounded at its remote terminal, and the apparatus at subscribers station is somewhat different. In the present case the telephone communicating apparatus 13 is placed in an earth- IOO connection, and a secrecyswitch, 12, is provided, which enables two stations upon the same line to be connected directly through their grounds, at the same time breaking the line to one side or the other, so as to prevent conversation from being heard at stations upon the disconnected portion of the line, while at intermediate stations the attempt to connect in the ground containing the telephone breaks the line, either momentarily or for an extended interval, and thus gives notice of the intrusion. A gravity-switch, g, short-circuits the bell when the telephone is removed from its support. As shown in the diagram, the lines are connected in pairs to the opposite poles of the chargingbattery M B, l and 2, 3 and 4, 5 and 6 being connected-2, 3, and 5 to one pole, and l, 4, and 6 to the other pole. This particular arrangement is by no means necessary, however, and the conditions are i'ullled it' any two are connected to one pole and the remainder to the other pole'.

Signals are given to the central ofce by means of circuit-breakin g keys of any preferred construction-such, for instance, as shown in Fig. 1. These keys are not indicated in Fig. 2.

The interruption of any one of the charged circuits upon any line will, under the above arrangement, affect only the bells upon .that line, as will be readily seen, since a complete circuitfor the chargin g-battcry still exists upon the remaining lines, provided, ot' course, that one at least of them is connected to the opposite pole of the battery from the others.

Signaling and conversation take place between the central office and subscribers in the ordinary manner. When the lines are to be connected at the central ofce for oral communication between subscribers upon different lines, the battery switch-levers of these lines are disconnected from the battery-strips N and I), and connection made between the proper levers 9 and a line-strip. At the subscribers stations theline is connected to earth and the telephone, and the continuity of the line beyond the subscriber is broken in the manner well understood.

Where several subscribers are placed upon the sameline, any two upon that line may communicate with one another by properly manip' ulating the switches 12.

As before intimated, the lines may be connected in any desired order to the opposite poles of the battery, and it is not necessary that any given line should be always restored to connection with the same pole of the charging-battery after having been used for oral communication. Care should be used, however, to preserve connection from both poles of the battery with several lines, and it is ofcourse always necessary that each pole should be connected with atleast oneline. It is obvious that under both the above arrangements many moditications in the details of the switches, both at the central office and subscribers stations, may be made without departing from the spirit of my invention,and that the bells and telephones at subscribers stations, both when circuits that are normally completely metallic are used and when grounded circuits are employed, may be differentl y located with relation to one another and to the lines. Some modificationsin these particulars thatI contemplate are reserved for the subject of future applications'.

What I claim as my invention is- 1. In a telephone-exchange system, a series of subscribers lines charged from opposite poles of a main or central oflce battery, substantially as described.

2. In a telephone-exchange system, a main or charging battery normally connected with both poles to subscribers lilies, in combination with means for shifting the circuitconnections of any line from one pole to the other of the battery, substantially as described. l

3. In a telephone-exchange system, the combination, with a series of subscribers lines, part charged from one pole and part from the other pole of a centra-lofce battery, of means for disconnecting each line from the battery, and means for connecting it directly to any other line without passing through the battery, for the purpose ot' oral communication, substantially as described.

4. In a telephone system, a series ot subscribers lines joined in pairs at their remote terminals, the lilies of each pair being connected to opposite poles ot' a charging-battery at the central office, snbstantially'as described.

5. In a telephone-exchange system containing a series ofsubscribers lines joined in pairs at their remote terminals, and connected at the central office to opposite poles of a chargingbattery, the combination, at each station of a line, of a telephone adapted to be placed in the-main-line circuit, and means for grounding the line at a point beyond the telephone and between the telephone and stations farther from the central office, substantially as described.

GEORGE V. COY.

Witnesses:

CHARLES E. BUELL, Jos. R. EDsoN.

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